Control relay unit

ABSTRACT

There is disclosed a relay unit for controlling a variety of controlled elements. The unit is extremely versatile in that it includes a plug-in transformer and plug-in relays. One or a plurality of relays may be plugged into the control unit and the unit may be wired to provide the additional function of an auxiliary switch.

3l7/140.5,135,137,139,136,101(CB),101 (radio), 101 (rug), 113; 307/17, 11, 141.8, 149, 150,135,139, 140,143,115, 117,112,118;

[5 6] References Cited UNITED STATES PATENTS 1,502,550 7/1924 Chamberlain 336/107 V 0 United States Patent 1111 3,566,195

[72] Inventor MkhRlW-Pmm 1,574,064 2/1926 Chamberlain 339/147 w st m m 2,309,563 1/1943 Abeel 317/230 211 Appl.N0- 697, 7 2,459,041 1/1949 Mitsch 307/112 221 Filed JIIII.15,1968 3,416,001 12/1968 Fistell 307/38 Patented Feb-23,1971 1,787,500 1/1931 Togami.... 317/137 A g a p rated 1,763,115 6/1930 Wermine 336/107x BerlimC nn- 1,930,523 10/1933 Landon 336/107x 1,988,733 1/1935 Helgason 336/107 2,784,354 3/1957 Gaubatz 317/113 1 CONTROLRELAYUFIT 2,808,575 10/1957- Karlson 317/101x 3,012,172 12/1961 KammeretaL. 317/101 52 U.S.Cl 317/137, 3,327,253 6/1967 Campbell 336/107x 317/101, 336/107,307/117,307/149 Primary Emmi-Hue T W Int.C|. x y w 5 qi ff n V 501 FieldofSearch 336/107;

I ABSTRACT: There is disclosed a relay unit for controlling a CONTROL RELAY UNIT BACKGROUND OF THE INVENTION There are many systems which utilize electrical relays to control various operations in response to preselected stimuli. However, in many such systems the relay installations are relatively complex and are wired into the system in such a manner that modification of the system is complex and repairs dif- A zone-heating system is one type of relay control system in which flexibility and ease of maintenance is desirable. In systems of this type there may be one or several circulators supplying heat to individual zones. The circulator supplying each zone is controlled by a separate thermostat within the zone. It would be highly desirable to provide a relay control unit wherein the relay functions could be readily expanded from one to a plurality of zones without extensive'modification. This would permit, for example, the establishing of an additional heating zone without making extensive wiring changes in the relay circuitry. It would also be desirable to provide such a system wherein the transformer supplying the individual relays could be readily replaced in the event of malfunction or when required to be replaced by one of larger capacity. It would also be desirable if such a control unit could function as an auxiliary switch for such other purposes as might be required by the particular installation.

SUMMARY OF THE INVENTION This invention comprises a prewired modular relay control unit having a plurality of sockets for receiving one or more plug-in relays and a socket for receiving a plug-in transformer. The unit is provided with a plurality of electrical terminals for connection to an external power supply, thermostats or other sensing devices, and for connection to the individual apparatus to be controlled.

BRIEF DESCRIPTION OF THE DRAWINGS One form of the invention is illustrated in the drawings wherein:

FIG. 1 is a perspective view of a relay-control unit in accordance with this invention mounted on a wall in its normal operating position;

FIG. 2 is an enlarged front view of the unit of FIG. I with the cover removed to expose the internal arrangement;

FIG. 3 is a cross section taken substantially along the line 3-3 of FIG. 2;

FIG. 4 is a top view of the unit with the cover in place and illustrating the manner in which the cover is removed;

FIG. 5 is a cross section taken substantially along the line 5-5 of FIG. 4;

FIG. 6 is an enlarged side view of the plug-in transformer employed in this unit, partially broken away to illustrate its internal construction;

FIG. 7 is an electrical schematic diagram of the unit of this invention wired for one type of installation;

FIG. 8 is a schematic diagram showing the unit wired to perform the additional function of an auxiliary switch; and

FIG. 9 is a schematic diagram showing the unit wired to function in a manner similar to that of either FIG. 7 or FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT The particular embodiment described herein is designed for a heating system having several heating zones. With particular reference to FIG. I, the relay unit 10 is shown mounted on a wall W in its usual operating position. The unit includes a generally box-shaped housing having a backwall 12, a left end wall 14, top and bottom walls 16 and 18 respectively, and a short right end wall 20. A generally L-shaped front cover 22 is mounted on the housing as shown in FIG. 4 by means of tabs 24 which extend through slots 26 in the left end wall to provide a hinged connection. The cover is secured ,in its closed position by means of a bolt 28 which extends through a slot in the cover and a hole in the right end wall 20. Suitable cooling vents 30 in the top wall 16 and bottom wall 18 provide adequate cooling when the cover is in place. The unit is mounted against the wall by means of keyhole slots 32 and screws 34 as shown most clearly in FIG. 5.

Extending inwardly from the top wall 16 and bottom wall 18 and positioned a short distance above the backwall 12 are a pair of support angles 36. Seated against the support angles and secured by a central mounting bolt 38 is a chassis board 40 of a suitable insulating material. Mounted in suitable openings in chassis board 40 are four sockets of the type commonly used for receiving vacuum tubes. The left socket, as seen in FIG. 2, is a transformer socket 42. The other three are relay sockets 44, 46, 48. These sockets are mounted in the usual manner with their terminals (not shown) arranged for back wiring in the space between chassis board 40 and backwall l2. Grounding of the wiring is prevented by means of an insulating sheet 50 positioned against the back wall 12. Across the top of chassis board 40 are three pairs 52, 54, 56 of thermostat terminals. Positioned in the lower right-hand corner of the board is a pair of auxiliary switch terminals 58. Across the bottom of chassis board 40 are five more pairs of terminals. The pair to theleft as seen in FIG. 2 form a power supply connection comprising neutral terminal 60a .and line terminal 60b. The remaining terminal pairs 62, 64, 66, 68 are aligned with the terminal 60. All the terminals illustrated are of the binding-screw, back-wired type, although it will be understood that other'types of terminals may be used. The wiring of these terminals and of the transformer and relay sockets is not illustrated pictorially but will be explained below by reference to the schematic diagram of FIG. 79.

Plugged into sockets 44, 46 and 48, respectively, are identical control relays 70, 72, 74. Each of these relays is a conventional double-pole, single-throw, coil-operated relay of the plug-in type. A novel plug-in transformer 76 is mounted in socket 42. Transformer 76 is of unique design in that it is provided with a housing 78 defining an opening 80 within which is mounted a plug 82 having the usual prongs and alignment stud for insertion into socket 42. The primary 84 and secondary 86 leads are connected to the prongs to provide the wiring configurations illustrated in FIGS. 79 to be described below. By means of this construction, transformer replacement, in the event of inadequate size or malfunction, is vastly simplified as it is merely necessary to unplug the old transformer and insert a new one in its place.

The internal wiring and operation of the relay unit of this invention may be best understood by reference to FIGS. 79. With particular reference to FIG. 7, there is illustrated a relay unit wired and connected to control a zone-heating system of up to 'three zones. In this modification, the auxiliary switch terminals 58 are not employed. Each of relays 70, 72, 74 includes a relay coil 70], 721, 741. Each of these coils in turn controls a pair of switching contacts which may be connected as illustrated in FIG. 7, thus switching contacts 702, 722, and 742 are connected in parallel with one another between line terminal 60b and one of the terminals 62. The switching contacts 703, 723, and 743 have their movable poles connected together and to the other of terminal 62, The other side of each contact is connected respectively to one of terminals 64, 66 or 68. The remaining terminals of pairs 64, 66, 68 are connected together and to the neutral terminal 60a. The primary winding 88 of transformer 76 is connected across the power supply terminals 60a, 60b. One side of the secondary winding 90 is connected to one end of each of the relay coils 701, 72I, 741 while the other end of the secondary winding 90 is connected to one each of the thermostat terminal pairs 52, 54, 56. The other terminal of each thermostat pair is connected to the remaining end of the respective relay coils.

The control relay unit of FIG. 7 is connected for operation by connecting the terminals 60a, 60b to a power supply 92 of volts AC For the particular application described, each of the thermostat pairs 52, 54, 56 is connected across a respective zone thermostat 94, 96, 98. Each of terminal pairs 64, 66,

68 is connected to the respective motor 100, 102, 104 of a zone circulator. The remaining terminal pair 62 is connected to a reverse aquastat 106 connected to sense the water temperature of the heatingboiler.

It will now be seen that, if any one of the zone thermostats closes due to a heating requirement, it will complete the circuit from transformer secondary 90 through its respective relay coil. For example, if thermostat 96 closes, relay coil 721 will be energized. This. will close its respective contacts 722, 723. Tracing the circuit from neutral terminal 60a'it will be seen that a closed circuit now exists through terminal pairs 66 and motor 102, through contacts 723 to one of terminal pairs 62, through the reverse aquastat 106, through the other terminal 62, and back to through contacts 722 to terminal 60b. Thus, as long as the aquastat 106' is closed, motor 102 will operate in response to closure of thermostat 96. The same is true of motor 100 controlled by thermostat 94 and motor 104 controlled by thermostat 98, the circuit being made in each instance through the aquastat 106.

The aquastat 106 is designed so that it remains closed as long as the water temperature is'sufficiently high. If the water temperature drops below a presetlevel, aquastat 106 will open and thereafter none of the circulator motors will be actuated regardless of the'conditionof its respective thermostat. This condition would persist until the temperature of the boiler water were increased to a sufficient value. If the aquastat is not needed or desired, it may be dispensed with by placing a jumper between terminals 62.

The flexibility of the relay circuit of FIG. 7 will be apparent when it is realized that each of the relays 70, 72, 74 is of the plug-intype. Accordingly, anyone relay and its function may be removed by merely unplugging it. Accordingly, the relay unit may be installed with, for example, only one zone, i.e., with only relay 70 in place. Thereafter, as zones are added to the installation, additional relays 72, 74 may be added as required and their respect'ivemotors and thermostats connected to the terminals provided.

FIG. 8 illustrates a modification wherein the relay unit 10 has the additional function of serving as an auxiliary switch. 1n the illustrated modification, the terminal 62 may be employed for the auxiliary switch function and may be connected, for example, to a burner. With this'arrangement, closure of any one of the three thermostats 94, 96, 98 will energize not only its corresponding circulator motor but also the burner connected to terminal 62. This is accomplished by a change in the wiring of the movable contacts of the relays. Thus, contacts 702, 722, and 742 are connected together and to one of terminals 62. Contacts 703, 723 and 743 are also connected together and to power supply terminal 601;. Assuming now that thermostat 96 closes, the relay coil 721 will be energized in the manner previously described, closing contacts 722, 723. Closure of contacts 723 will place motor 102 directly across the power supply terminals .60a,"60b and the motor will be energized. Closure of contacts 722 will close the circuit across terminal 62, thus closing any-circuit which may be connected in the absence of these conductors, the function of this unit function in the same manner as the circuits of FIG. 7 or 8, as

will be identical to that of. FIG. 7. The auxiliary switch terminals 58 would then be inoperative. ln order to provide the auxiliary switch function, a conductor is connected from terminal 60b to the right-hand one'of terminal pair 62, and terminals 58 are connected across the paralleled contacts 702, 722, 742. It will now be apparent upon tracing the circuit that closure of any thermostat will actuate its correspondirzg motor through the umper between the terminal 62 and 60 It will also be noted that auxiliary switch terminals 58 are now connected in parallel with the contacts702, 722, 742 so that closure of any one of these contacts will also complete any circuit connected to terminals 58.

It is believed that the many advantages of this invention will now be apparent to those skilled in the art. It will also be apparent that,although the described embodiment has been directed to the use of the invention in controlling a heating installation, many other applications may be made. Any type of sensing device may be employed in place of the thermostats and any type of appliance .may be connected in place of the motors. It will also be apparentthat a number of variations and modifications may be made in this invention without departing from its spirit and scope. Accordingly, the foregoing description is to be construed as illustrative only, rather than limiting. The invention is limited only by the scope of the following claims. 1

Iclaim:

1. A control relay unit which comprises a chassis; a transformer socket mounted on said chassis; a plurality of relay sockets mounted on said chassis; a plug-in transformer insertable into said transformer socket; at least one plug-in relay means, each relay means beinginsertable into one of said relay sockets; a plurality of input terminal pairs mounted on said chassis; a plurality of output terminal pairs mounted on said chassis; conductor means connectable between said transformer socket and a source of AC power to energize the primary of said transformer when inserted in said transformer socket; means connecting the operating coil of each of said relays in series with a respective pair of input terminals when the terminals are short circuited across the secondary of said transformer when said relays are inserted in said relay sockets; and means connecting the contacts of each of said relays when energized in series with a respective pair of output terminals when a load is connected between the respective pair of output terminals across said power source when said relays are inserted in said relay sockets.

2. The unit of claim 1 additionally comprising: a pair of auxiliary terminals mounted on said chassis; and means connecting said auxiliary terminals when connected in circuit with each other in series with each of said relay contacts and its corresponding output terminals.

3. The unit of claim 1 wherein each of said relay means includes at least first and second switching contacts, said first contacts of each relay being connected in series with one of said output terminal pairs and additionally comprising: a pair of switch terminals mounted on said chassis; and means connecting said switch terminals in parallel with all of said second switching contacts.

4. The unit of claim 1 additionally comprising: a housing including a backwall; a cover on said housing; and mounting means retaining said chassis in said housing spaced from said backwall to accommodate said connecting means therebetween. 

1. A control relay unit which comprises a chassis; a transformer socket mounted on said chassis; a plurality of relay sockets mounted on said chassis; a plug-in transformer insertable into said transformer socket; at least one plug-in relay means, each relay means being insertable into one of said relay sockets; a plurality of input terminal pairs mounted on said chassis; a plurality of output terminal pairs mounted on said chassis; conductor means connectable between said transformer socket and a source of AC power to energize the primary of said transformer when inserted in said transformer socket; means connecting the operating coil of each of said relays in series with a respective pair of input terminals when the terminals are short circuited across the secondary of said transformer when said relays are inserted in said relay sockets; and means connecting the contacts of each of said relays when energized in series with a respective pair of output terminals when a load is connected between the respective pair of output terminals across said power source when said relays are inserted in said relay sockets.
 2. ThE unit of claim 1 additionally comprising: a pair of auxiliary terminals mounted on said chassis; and means connecting said auxiliary terminals when connected in circuit with each other in series with each of said relay contacts and its corresponding output terminals.
 3. The unit of claim 1 wherein each of said relay means includes at least first and second switching contacts, said first contacts of each relay being connected in series with one of said output terminal pairs and additionally comprising: a pair of switch terminals mounted on said chassis; and means connecting said switch terminals in parallel with all of said second switching contacts.
 4. The unit of claim 1 additionally comprising: a housing including a backwall; a cover on said housing; and mounting means retaining said chassis in said housing spaced from said backwall to accommodate said connecting means therebetween. 